Modular plugs, which are used to terminate retractile cords that connect a telephone base to a handset, provide a customer as well as an installer with the capability of easily changing cords by removing the plugs from jacks in the base and handset and then reinstalling a new or refurbished cord. Newly obtained telephones are easily connected to existing wall terminals by inserting a modular plug which terminates one end of a line cord into a jack in the telephone base and the plug at the other end of the cord into a jack in the wall terminal.
Modular plugs for terminating telephone cords are shown, for example, in U.S. Pat. Nos. 3,699,498 and 3,761,869 which issued Oct. 17, 1972 and Sept. 25, 1973, respectively, both in the names of E. C. Hardesty, C. L. Krumreich, A. E. Mulbarger, Jr., and S. W. Walden. Jacks which are adapted to receive modular plugs that terminate new style flat telephone cords are shown for example in previously identified U.S. Pat. No. 3,699,498 and in U.S. Pat. Nos. 3,850,497 and 3,990,764, the latter two patents being issued on Nov. 26, 1974 and Nov. 9, 1976, respectively.
A jack which is provided in the wall terminal usually includes a single outlet for connecting a station instrument such as, for example, the telephone set to an associated telephone line. However, there are some situations in which it is desirable to be able to connect two station instruments such as, for example, a telephone answering device and an adjacent telephone set to the telephone line in parallel at the same location. There are other situations where it may be desirable to be able to connect an external signal source for an auxiliary power supply to telephone station equipment at the same location on the premises, such as, for example, to provide power to an incandescent lamp mounted within a telephone set for illuminating a dial or an array of pushbuttons. As should be evident, there is a need for an adapter to provide multiple access to a telephone line at a single wall terminal.
A prior art adapter which serves the aforementioned needs is shown for example, in D. R. Snyder defensive publication No. T958,009 published May 3, 1977. The adapter includes a jack portion and a plug portion, having a plurality of blade-like terminals that make electrical connections with conductors which are positioned within the adapter. Each conductor is doubled over within the plug portion, and both ends of each conductor are terminated with a wire spring contact. The contacts are exposed within a pair of externally communicating cavities of the jack portion to engage terminals of a modular plug which is inserted into each cavity to connect the terminals in the plug to contacts of a wall terminal jack. See also U.S. Pat. No. 4,061,411.
While the adapter disclosed and claimed in the aforementioned publication provides a means for connecting two modular plugs to a wall terminal, it includes a plurality of contacts and terminals as well as interconnecting conductors extending between the plug and jack portions. It would be most desirable to provide an adapter for interconnecting the plugs and the wall terminal while minimizing the number of components comprising the adapter in order to facilitate its manufacture.